Spirit-level



(No Model;)

B. BARKER.

SPIRIT LEVEL.

No. 325,479. Patented Sept. 1, 1885.

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SPIRlT-LEVEL.

tEPHCIFICATIGN forming part of Letters Patent No. 325,479, dated September 1, 1885.

Application filed October 3:2, 1884.

T0 ctZZ whom it may concern:

Be it known that I, ROBERT BARKER, of Lansing, in the county of Ingham and State of Michigan, have invented new and useful 5 Improvements in Spirit-Levels; and I do here- :5 of the proper width to receive the tile, and at any desired depth, and in order that the water may run off through such tile it is necessary that a falling grade of the bottom of such cut shall be established. This has been a work of great difficulty for the ordinary farmer to accomplish without the aid of a practical surveyor.

The object of the present invention is to place before the public at a moderate expense a device which will enable any one of ordinary intelligence to fix the grade under the circumstances above described.

Figure 1 is a perspective of my improved spiritlevel. Fig. 2 is a sectional perspective Fig. 3 is a vertical central cross-section. Fig. 4 is a modification of Fig. 1. Fig. 5 is a detail view of the sliding plate 0, its rack, and rack-wheel.

In the accompanying drawings, which form 5 a part of this specification, A represents the bed of the spirit-level, with its upper and lower edges perfectly parallel. In its whole length, upon its upper edge, there is formed a nearly semicircular groove or channel, a, and in its lower edge, midway between the two ends, is a socket, by means of which the level is se cured to a grade stake or tripod.

At one end of the implement is secured a slotted scale-plate, l3, and behind, or within this scale-plate, there is arranged a sliding plate, 0, adapted to be raised or lowered by means of a thumb-shaft, D, carrying a rackwheel engaging with rack-teeth on the sliding plate; and as this method of giving motion to a rack is so familiar the details are not shown in the drawings. Through the center and near the top of this sliding plate there is a small (No model.)

sight-hole, c, punctured or formed. At one side, at the opposite end of the bed, there is also provided a scale and a sliding plate, E, in which, near the top, are formed two circular apertures, D. A hair-line slit, E, forming a sight, is cut from one of the circular openings to theother, as shown. By this construction of sight, and the circular openings on either side, the operator not only obtains a very fine accurate sight, but through such openings has a very clear vision beyond the implement. This slide-plate E may be secured to this end of the bed in any desired manner, so that it may have a vertical motion, as it may be necessary to elevate or depress the sight.

In the bottom of the channel a, and between the scale-plate B and the central position of the socket b, is secured a spiritlevel, F, so that the upper line of the level will be upon the same plane as the bottom of the channel a.

It will readily be seen that by the use of this implement a regular grade of any desired pitch may be established, as its employment renders it unnecessary to bring into play any of the higher problems of mathematics, so necessary to be used in engineering work.

The device is so simple and its application so easily understood that a further description thereof is deemed unnecessary.

In Fig. 4 is a modification of the device as shown in Fig. 1. This modification shows the level proper secured to the grooved bed heretofore described,with the scales and sights arranged as already pointed out. I consider this modification to be within the spirit of my invention.

I deem it important that the groove or slot extend the whole length of the bed, for this construction serves a twofold purposeviz., the support of the sights at the ends, thus requiring less elevation of the sights above the points of support, and to prevent the dazzling effect of bright light when sighting close to the surface, serving in part the function of a tube.

I am aware of the Patents Nos. 60,346 and 102,882, and make no claim to the construction shown therein as forming part of my invention.

W'hat I claim as my invention is- 1. The combination, in a leveling-instrument, of the bed A, the slotted scalcplate B,

secured to one end thereof, and the sliding plate 0, having sight-hole c, said plate B forming a guide and also a protection for said sliding plate, substantially as described.

2; The combination, with the bed grooved longitudinally from end to end in its upper edge and providedwith the spirit-tube in the bottom of said groove, of a slotted scale-plate secured to one end of said bed, and a vertically-reciprocating slide-sight actuated by a rack-wheel at the other end of said bed, sub-v stantially as specified.

3. The combination, in a leveling-instrument of the grooved bed A, provided with a spirit-level in the bottom of said groove, the 15 slotted scale-plate secured tosaid bed, the

sliding plate 0, having sight-hole c, and guided and protected by said plate B, and provided also with a rack, and the pinion provided with a thun1b-nut,'D,all constructed,arranged, 20

and operating substantially as herein shown and described.

ROBT. BARKER.

Witnesses:

O. P. TEN EYCK, J. M. THUN. 

